Capacitor structures for use in integrated circuits and methods of their manufacture. The capacitor structures include a bottom electrode, a top electrode and a dielectric layer interposed between the bottom electrode and the top electrode. The capacitor structures further include a metal oxide buffer layer interposed between the dielectric layer and at least one of the bottom and top electrodes. Each metal oxide buffer layer acts to improve capacitance and reduce capacitor leakage. The capacitors are suited for use as memory cells and apparatus incorporating such memory cells, as well as other integrated circuits.
Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A method of forming a capacitor, comprising: forming a tungsten nitride, bottom electrode layer; forming a tungsten oxide buffer layer overlying the bottom electrode layer; annealing the buffer layer to form an orthorhombic structure; forming a dielectric layer overlying the tungsten oxide buffer layer; and forming a top electrode layer overlying the dielectric layer.
A method for building a capacitor involves first creating a bottom electrode made of tungsten nitride. Next, a buffer layer of tungsten oxide is formed on top of this electrode. This buffer layer is then heated (annealed) to give it a specific crystal structure called orthorhombic. After that, a dielectric (insulating) layer is deposited on top of the tungsten oxide. Finally, a top electrode is formed on top of the dielectric layer.
2. The method of claim 1 , further comprising patterning the top electrode layer, the buffer layer, the dielectric layer, and the bottom electrode layer to define the capacitor.
To build a capacitor, follow the method: create a bottom electrode of tungsten nitride, form a tungsten oxide buffer layer on it, anneal the buffer layer to an orthorhombic structure, deposit a dielectric layer, and form a top electrode. After these layers are created, the top electrode layer, dielectric layer, buffer layer, and bottom electrode layer are etched (patterned) to define the shape and size of the capacitor.
3. The method of claim 1 , wherein the method is performed in the order presented.
To build a capacitor, follow the method: create a bottom electrode of tungsten nitride, form a tungsten oxide buffer layer on it, anneal the buffer layer to an orthorhombic structure, deposit a dielectric layer, and form a top electrode. This process must be performed in the exact order as listed for proper capacitor function.
4. The method of claim 1 , wherein forming the bottom electrode includes forming WN n ; 2<n<=6.
To build a capacitor, create a bottom electrode of tungsten nitride, form a tungsten oxide buffer layer on it, anneal the buffer layer to an orthorhombic structure, deposit a dielectric layer, and form a top electrode. When creating the tungsten nitride bottom electrode, the composition of tungsten nitride should be WNn, where 'n' is a value between 2 and 6 (2<n<=6).
5. A method of forming a capacitor, comprising: forming an insulating layer on a substrate; forming an opening in the insulating layer, wherein the opening has a bottom portion overlying an exposed portion of the substrate and sidewall portions defined by the insulating layer; forming a bottom electrode layer, which includes tungsten nitride, overlying the insulating layer, the exposed portion of the substrate and the sidewall portions; forming an orthorhombic tungsten oxide buffer layer overlying the bottom electrode layer; forming a dielectric layer overlying the tungsten oxide buffer layer; forming a top electrode layer overlying the dielectric layer; and patterning the top electrode layer, dielectric layer, tungsten oxide buffer layer and bottom electrode layer to thereby define the capacitor.
A method for building a capacitor begins with an insulating layer on a substrate. An opening is made in this layer, exposing a portion of the substrate at the bottom and creating sidewalls. A bottom electrode of tungsten nitride is formed, covering the insulating layer, the exposed substrate, and the sidewalls. An orthorhombic tungsten oxide buffer layer is then formed on top of the bottom electrode. A dielectric layer goes on top of the buffer layer, followed by a top electrode. Finally, these top electrode layer, dielectric layer, tungsten oxide buffer layer and bottom electrode layer are patterned to define the final capacitor structure.
6. The method of claim 5 , wherein forming the tungsten oxide buffer layer comprises oxidizing the bottom electrode layer to form the buffer layer, and annealing the buffer layer.
To build a capacitor, start with an insulating layer on a substrate and make an opening. Form a tungsten nitride bottom electrode. To create the tungsten oxide buffer layer, oxidize the tungsten nitride bottom electrode, then heat treat (anneal) this oxidized layer. This oxidation and annealing process creates the buffer layer that improves capacitor performance. Deposit a dielectric layer and a top electrode, then pattern all layers to define the capacitor.
7. The method of claim 6 , wherein the buffer layer is annealed at a temperature of over 650 degrees Celsius.
To build a capacitor, start with an insulating layer on a substrate and make an opening. Form a tungsten nitride bottom electrode. To create the tungsten oxide buffer layer, oxidize the tungsten nitride bottom electrode, then heat treat (anneal) this oxidized layer *at a temperature greater than 650 degrees Celsius*. This oxidation and annealing process creates the buffer layer that improves capacitor performance. Deposit a dielectric layer and a top electrode, then pattern all layers to define the capacitor.
8. The method of claim 5 , wherein the buffer layer is annealed at a temperature of at least 700 degrees Celsius.
To build a capacitor, start with an insulating layer on a substrate and make an opening. Form a tungsten nitride bottom electrode. Form an orthorhombic tungsten oxide buffer layer on top of the bottom electrode. To create the tungsten oxide buffer layer, oxidize the tungsten nitride bottom electrode, then heat treat (anneal) this oxidized layer *at a temperature of at least 700 degrees Celsius*. This oxidation and annealing process creates the buffer layer that improves capacitor performance. Deposit a dielectric layer and a top electrode, then pattern all layers to define the capacitor.
9. The method of claim 5 , wherein forming the bottom electrode includes forming WN n ; 2<n<=6.
To build a capacitor, start with an insulating layer on a substrate and make an opening. Form a tungsten nitride bottom electrode, where the tungsten nitride composition is WNn, with 'n' between 2 and 6 (2<n<=6). Then, form an orthorhombic tungsten oxide buffer layer on top of the bottom electrode. A dielectric layer goes on top of the buffer layer, followed by a top electrode. Finally, these layers are patterned to define the capacitor.
10. A method of forming a capacitor, comprising: forming an insulating layer on a substrate; forming an opening in the insulating layer, wherein the opening has a bottom portion overlying an exposed portion of the substrate and sidewall portions defined by the insulating layer; forming a tungsten nitride bottom electrode layer overlying the insulating layer, the exposed portion of the substrate and the sidewall portions; forming a tungsten oxide buffer layer overlying the bottom electrode layer, wherein the buffer layer has an orthorhombic crystal structure; forming a dielectric layer overlying the buffer layer; forming a top electrode layer overlying the dielectric layer; and patterning the top electrode layer, dielectric layer, buffer layer and bottom electrode layer to thereby define the capacitor.
A method for building a capacitor begins with an insulating layer on a substrate. An opening is made in this layer, exposing a portion of the substrate and creating sidewalls. A tungsten nitride bottom electrode is formed, covering the insulating layer, the exposed substrate, and the sidewalls. A tungsten oxide buffer layer *with an orthorhombic crystal structure* is then formed on top of the bottom electrode. A dielectric layer goes on top of the buffer layer, followed by a top electrode. Finally, these layers are patterned to define the final capacitor structure.
11. The method of claim 10 , wherein forming the bottom electrode includes forming WN 2 .
To build a capacitor, start with an insulating layer on a substrate and make an opening. Form a tungsten nitride bottom electrode, where the tungsten nitride composition is specifically WN2. Then, form a tungsten oxide buffer layer with an orthorhombic crystal structure on top of the bottom electrode. A dielectric layer goes on top of the buffer layer, followed by a top electrode. Finally, these layers are patterned to define the capacitor.
12. A method of forming a capacitor, comprising: forming an insulating layer on a substrate; forming an opening in the insulating layer, wherein the opening has a bottom portion overlying an exposed portion of the substrate and sidewall portions defined by the insulating layer; forming a tungsten nitride bottom electrode layer overlying the insulating layer, the exposed portion of the substrate and the sidewall portions; oxidizing the bottom electrode layer to form a tungsten oxide buffer layer overlying the bottom electrode layer; annealing the buffer layer to an orthorhombic crystal lattice; forming a dielectric layer overlying the buffer layer; forming a top electrode layer overlying the dielectric layer; and patterning the top electrode layer, dielectric layer, buffer layer and bottom electrode layer to thereby define the capacitor.
A method for building a capacitor begins with an insulating layer on a substrate. An opening is made in this layer, exposing a portion of the substrate and creating sidewalls. A tungsten nitride bottom electrode is formed, covering the insulating layer, the exposed substrate, and the sidewalls. The tungsten nitride layer is then oxidized to create a tungsten oxide buffer layer. This buffer layer is annealed to give it an orthorhombic crystal lattice. A dielectric layer goes on top of the buffer layer, followed by a top electrode. Finally, these layers are patterned to define the capacitor.
13. The method according to claim 12 , wherein annealing the buffer layer includes annealing at a temperature of at least 700 degrees Celsius.
To build a capacitor, start with an insulating layer on a substrate and make an opening. Form a tungsten nitride bottom electrode; oxidize it to form a tungsten oxide buffer layer. Anneal the buffer layer *at a temperature of at least 700 degrees Celsius* to achieve an orthorhombic crystal lattice. Then deposit a dielectric layer and a top electrode. Finally, pattern all layers to define the capacitor.
14. The method of claim 12 , wherein forming the bottom electrode includes forming WN 2 .
To build a capacitor, start with an insulating layer on a substrate and make an opening. Form a tungsten nitride bottom electrode, specifically using WN2. Oxidize it to form a tungsten oxide buffer layer. Anneal the buffer layer to achieve an orthorhombic crystal lattice. Then deposit a dielectric layer and a top electrode. Finally, pattern all layers to define the capacitor.
15. A method of forming a capacitor, comprising: forming an insulating layer on a substrate; forming an opening in the insulating layer, wherein the opening has a bottom portion overlying an exposed portion of the substrate and sidewall portions defined by the insulating layer; depositing a tungsten nitride bottom electrode layer overlying the insulating layer, the exposed portion of the substrate and the sidewall portions; oxidizing the bottom electrode layer to form a tungsten trioxide buffer layer overlying the bottom electrode layer; annealing the buffer layer at a temperature of at least 700 degrees Celsius to have an orthorhombic crystal lattice; depositing a tantalum oxide dielectric layer overlying the buffer layer; depositing a metal top electrode layer overlying the dielectric layer; and patterning the top electrode layer, dielectric layer, buffer layer and bottom electrode layer to thereby define the capacitor.
A method for building a capacitor: Start with an insulating layer on a substrate and create an opening. Deposit a tungsten nitride bottom electrode. Oxidize this electrode to create a tungsten trioxide buffer layer. Anneal the buffer layer at a temperature of at least 700 degrees Celsius to obtain an orthorhombic crystal lattice. Deposit a tantalum oxide dielectric layer. Deposit a metal top electrode. Pattern all these layers to define the capacitor.
16. The method of claim 15 , wherein the metal top electrode includes a noble metal.
To build a capacitor, start with an insulating layer on a substrate and make an opening. Deposit a tungsten nitride bottom electrode; oxidize it to form a tungsten trioxide buffer layer. Anneal the buffer layer at 700C+ to get an orthorhombic lattice. Deposit a tantalum oxide dielectric layer. Deposit *a top electrode made of a noble metal*. Finally, pattern all layers to define the capacitor.
17. The method of claim 15 , wherein the top electrode includes a platinum alloy.
To build a capacitor, start with an insulating layer on a substrate and make an opening. Deposit a tungsten nitride bottom electrode; oxidize it to form a tungsten trioxide buffer layer. Anneal the buffer layer at 700C+ to get an orthorhombic lattice. Deposit a tantalum oxide dielectric layer. Deposit *a top electrode made of a platinum alloy*. Finally, pattern all layers to define the capacitor.
18. A method of forming a capacitor, comprising: forming a first electrode layer, wherein the first electrode layer comprises a metal nitride having a metal component; forming a buffer layer having an orthorhombic crystal structure overlying the first electrode layer, wherein the buffer layer comprises a metal oxide having a composition of the form MO x , wherein M is a metal component selected from the group consisting of chromium, cobalt, hafnium, iridium, molybdenum, niobium, osmium, rhenium, rhodium, ruthenium, tantalum, titanium, tungsten, vanadium and zirconium; forming a dielectric layer overlying the buffer layer; forming a second electrode layer overlying the buffer layer, wherein the second electrode layer comprises a metal nitride having a metal component; and patterning the second electrode layer, dielectric layer, buffer layer and first electrode layer to thereby define the capacitor.
A method for forming a capacitor includes forming a first electrode layer made of a metal nitride. Then, a buffer layer with an orthorhombic crystal structure, made of a metal oxide (MOx, where M is chromium, cobalt, hafnium, iridium, molybdenum, niobium, osmium, rhenium, rhodium, ruthenium, tantalum, titanium, tungsten, vanadium, or zirconium), is formed on top. A dielectric layer is formed on the buffer layer, followed by a second electrode layer of a metal nitride. These layers are then patterned to define the capacitor.
19. The method of claim 18 , wherein the metal component of the first electrode layer is tungsten.
For forming a capacitor: Form a first electrode (metal nitride), where *the metal in the nitride is tungsten*. Form an orthorhombic buffer layer (metal oxide, MOx, where M is Cr, Co, Hf, Ir, Mo, Nb, Os, Re, Rh, Ru, Ta, Ti, W, V, or Zr). Deposit a dielectric layer and a second metal nitride electrode. Pattern all to define the capacitor.
20. The method of claim 18 , wherein the metal component M of the buffer layer is selected to be the same as the metal component of the first electrode layer.
For forming a capacitor: Form a first electrode (metal nitride). Form an orthorhombic buffer layer (metal oxide, MOx, where M is Cr, Co, Hf, Ir, Mo, Nb, Os, Re, Rh, Ru, Ta, Ti, W, V, or Zr), *choosing M to be the same metal as in the first electrode*. Deposit a dielectric layer and a second metal nitride electrode. Pattern all to define the capacitor.
21. The method of claim 18 , wherein the dielectric layer comprises a metal oxide dielectric material.
For forming a capacitor: Form a first electrode (metal nitride). Form an orthorhombic buffer layer (metal oxide, MOx, where M is Cr, Co, Hf, Ir, Mo, Nb, Os, Re, Rh, Ru, Ta, Ti, W, V, or Zr). Deposit *a dielectric layer made of a metal oxide*. Deposit a second metal nitride electrode. Pattern all to define the capacitor.
22. The method of claim 18 , wherein the method is performed in the order presented.
A method for forming a capacitor includes forming a first electrode layer made of a metal nitride. Then, a buffer layer with an orthorhombic crystal structure, made of a metal oxide (MOx, where M is chromium, cobalt, hafnium, iridium, molybdenum, niobium, osmium, rhenium, rhodium, ruthenium, tantalum, titanium, tungsten, vanadium, or zirconium), is formed on top. A dielectric layer is formed on the buffer layer, followed by a second electrode layer of a metal nitride. These layers are then patterned to define the capacitor. *The order of these steps is important.*
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
October 31, 2007
June 25, 2013
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